1. Field to the Invention
The present invention is directed to a polarized electromagnet relay, and more particularly to a flat and compact type of polarized electromagnet relay with at least one contact assembly which is arranged between the planes of the yoke of an electromagnet block and a base plate of the relay to be actuated for contact switching by an armature block driven to reciprocate between two positions in response to the excitation of the electromagnet block.
2. Description of the Prior Art
The above relay construction of arranging the contact assembly between the planes of the yoke of an electromagnet block and a base plate of the relay is known to be effective for attaining a compact relay structure with a reduced width as shown, for example, in U.S. Pat. No. 3,634,793. This patent discloses a pair of contact assemblies received between the yoke and the base plate. An excitation coil has its axis aligned in the plane of the opposed side yoke legs and has its upper portion projecting above that plane, which portion adds an extra height to the relay dimension and therefore is desired to be eliminated for the purpose of attaining a more compact relay construction with reduced height as well as width. The above adverse effect will be more serious when the coil is required to have a greater number of turns within a limited length. Another prior polarized relay is disclosed in U.S. Pat. No. 3,518,592 which is employable in providing the above relay construction. This patent utilizes an E-shaped yoke with a pair of opposed side legs and a center leg forming a core around which a coil is wound. However, with this yoke having the center leg or core arranged in the same plane of the side legs of the yoke, the coil wound around the core cannot avoid projecting beyond the plane of the side legs and certainly adds an extra height to the relay construction. In addition, this yoke configuration can afford less spacing between the center leg and the side legs, thus limiting the number of coil turns to a lesser extent. That is, the number of coil turns can be increased only by elongating the core, or increasing the length of the coil, which results in an increased length of the overall relay construction and is therefore should be eliminated for designing a more compact or miniaturized relay. Therefore, an optimal space utilization for the coil is most desirous in order to attain a more compact arrangement of this kind of the polarized relay without impairing electrical insulation between the parts of the relay.